In the case of digital video applications, it is often helpful to redimension it as a function of the display norm used. These redimensionings may impair the sharpness of the contour zones, and hence the quality of the image displayed.
Conventionally, to limit the visual artifacts impairing the contours of the processed image, in particular owing to the approximations stemming from the use of a linear procedure, a post-filtering (for example to perform a sharpness processing as described in U.S. Pat. No. 6,847,738 in the name of Philips) can be carried out, in particular at the level of the contour zones.
However, a post-filtering may attenuate one type of artefact (for example the appearance of halos, with the aid of a linear compensation filter) but accentuate another type.
Furthermore, the use of an extra filter adds constraints on the aperture of the signal sampling window, which may not be as narrow as desired, thereby accentuating the degradation of the processed image.